1. Field of the Invention
The present invention relates to a centrifugal fan.
2. Description of the Related Art
Centrifugal cooling fans are typically installed in electronic devices, such as computers, to cool electronic components. Such a cooling fan is arranged to rotate an impeller to produce an air current travelling in a centrifugal direction. An electronic component inside the electronic device is thus cooled by the air current. The air current produced by the impeller is sometimes used to cool a circuit designed to drive the cooling fan. A known cooling fan is described in, for example, US 2011/0103011.
In recent years, electronic devices have been becoming more and more sophisticated in functionality, and there has accordingly been a demand for improved cooling performance of blower fans. US 2011/0103011 describes a heat exchanger 2100 including a heat transfer structure 2105 and a heat conducting structure 2110. In the heat exchanger 2100, a. CPU 2120, which is a heat source, is arranged inside the heat conducting structure 2110. Heat of the CPU 2120 is discharged to an outside through the heat transfer structure 2105, which is made of a metal.
To increase heat dissipation efficiency of the heat exchanger 2100 described in US 2011/0103011, an air volume needs to be increased by increasing the rotation rate of the heat transfer structure 2105. However, the heat transfer structure 2105 of the heat exchanger 2100 described in US 2011/0103011 is entirely made of the metal. Accordingly, the heat transfer structure 2105 has a great weight, and it is therefore difficult to increase the rotation rate of the heat transfer structure 2105 to increase the volume of the air current.